CTLA4 gene polymorphisms and multiple sclerosis in Northern Ireland.

Four CTLA4 polymorphisms were investigated in a Northern Irish collection of relapsing-remitting (RR) and primary-progressive (PP) multiple sclerosis (MS) patients. The CTLA4 promoter (-318 C/T), exon 1 (+49 A/G) and intergenic CT60 SNPs, as well as a microsatellite found in the 3' UTR (AT(n)) were analysed in 246 RRMS, 84 PPMS and 158 healthy controls. The A allele of the exon 1 +49 A/G SNP (OR=1.36; 95% CI=1.11-1.81; P=0.038), and more so the AA genotype (OR=1.70; 95% CI=1.11-2.60; P=0.015) were associated with RR, but not PPMS. In the PPMS population, overall allele distribution of the AT(n) microsatellite was significantly different from that in the healthy controls. We did not find any association with the promoter (-318 C/T) or intergenic CT60 SNPs in either of the disease cohorts. In concordance with several recent studies, we detected a trend toward higher carriage rates of the +49 G allele in PP vs RR MS patients (66.7% vs 58.9%), though this was not significant. Our data highlight the CTLA4 +49 A/G and 3'UTR polymorphisms as potential modifiers of disease course in MS.

Pharmacogenomics of responsiveness to interferon IFN-beta treatment in multiple sclerosis: a genetic screen of 100 type I interferon-inducible genes.

OBJECTIVES: Interferon IFN-beta is indicated for the treatment of multiple sclerosis. A significant proportion of patients show a poor clinical response to therapy. Type I interferon exerts its effect at least partially through interaction of specific transcription factors with interferon-stimulated response elements (ISREs), mostly located in promoter regions of its target genes. We hypothesized that polymorphisms may occur within or close to ISRE elements, altering type I interferon inducibility and ultimately leading to a modified clinical response in carriers. METHODS: We selected 100 ISRE-containing genes and sequenced their promoter regions in small genomic deoxyribonucleic acid pools of responding and nonresponding patients, as well as healthy control subjects. A selection of polymorphisms discovered by this approach was scrutinized subsequently in a collection of individual deoxyribonucleic acid samples. RESULTS: We identified 4 genes containing polymorphisms associated with response to recombinant IFN-beta: IFNAR1 (P = .036), LMP7 (P = .002; odds ratio [OR], 6.37 [95% confidence interval (CI), 1.84-24.1]), CTSS (P = .02; OR, 0.38 [95% CI, 0.18-0.84]), and MxA (P = .015; OR, 3.37 [95% CI, 1.11-11.4]). Logistic regression analysis with treatment outcome used as the dependent variable and genotype as the independent variable revealed 2 genes, LMP7 (OR, 0.55 [95% CI, 0.34-0.89]) and MxA (OR, 0.41 [95% CI, 0.19-0.88]), that were independently associated with treatment response. CONCLUSIONS: Our work confirms and extends previous indications for a polygenic mechanism involved in bringing about responsiveness to recombinant IFN-beta. The identification of 2 genes active in the antigen processing and presentation cascade; that is, LMP7, coding for the proteasome subunit beta, and CTSS, coding for cathepsin S; as potential response modifiers may identify this pathway as being of particular relevance to phenotypic expression of response heterogeneity.

A genome wide scan for association with multiple sclerosis in a N. Irish case control population.

In order to screen the genome for linkage disequilibrium (LD) in multiple sclerosis (MS), we typed 2537 microsatellite markers in separately pooled DNA from 200 cases and 200 controls from N. Ireland. Twenty two markers showing significant evidence of association were identified including three from the HLA region on chromosome 6p21. Putative candidate genes mapping close to the 19 novel markers include the IL10RA and CD3E genes on 11q23 (which both lie close to the marker D11S1998). Individual typing of the marker D11S1998 confirmed its association.